1. Field of the Invention
This invention relates generally to archival methods and more particularly to a method and apparatus for physically defining analog data on a durable medium for long term storage and retrieval using processing techniques related to those used in semiconductor manufacturing.
2. Description of the Prior Art
Recently, international attention has been focused on the subject of “Analog Data Storage” i.e. storage of text and images in the analog format on durable media. The storage format is such that retrieval of the data only requires magnification of the data onto a viewing screen using simple optical methods, akin to the process currently used for the viewing of microfiche.
Although Microfiche/microfilms are the current accepted method for analog archival of data, this technology does not serve the purpose of truly long term archival. Microfiche/microfilms require special environmental conditions for storage of the film. Accordingly, Microfiche is not a durable medium for archival storage over long periods of time. Secondly, microfiche/microfilms degrade despite environmental controls in as short a span as 30-50 years thus requiring re-copying onto new film. Re-copying leads to some loss of data due to degradation of resolution. Thus the current technology available for analog data storage for archival purposes does not provide long-term (>1000 years) storage of data on durable media capable of withstanding all forms of corrosive environments. Additionally, storage of data on microfilms becomes expensive in the long run because of the need for environmental controls and re-copying at the media end of life.
Archivists look to analog storage of data because they are concerned with preservation of text and images over time measured in millennia. Furthermore, archivists desire that the retrieval of the data should not be dependent on software or hardware devices such as the case for digital storage of data.
The industry has made big strides in digital storage of data where relatively high densities of data can be stored in various media such as compact discs, digital versatile discs, storage drives etc. and can be retrieved at extremely high speeds using computing software/hardware. The key problem in this form data storage is that it is dependent on the digital technology available at any given time and suffers from software/hardware obsolescence in relatively short time spans. A good example is the 5¼ floppy storage disc and reader both of which were commonly in use for digital data storage in the 1970s and 80s. Today this form of storage does not exist and has been replaced by other digital storage devices capable of higher densities.
Accordingly, the need remains for an improved method for implementing archival storage and retrieval of analog data.